排序方式: 共有28条查询结果,搜索用时 15 毫秒
1.
2.
Xinman Chen Guangheng Wu Hailei Zhang Ni Qin Tao Wang Feifei Wang Wangzhou Shi Dinghua Bao 《Applied Physics A: Materials Science & Processing》2010,100(4):987-990
We report on reversible bipolar resistance switching effects in multiferroic BiFeO3 thin films without electroforming. The BiFeO3 thin films with (110) preferential orientation were prepared on LaNiO3-electrodized Si substrates with a Pt/BiFeO3/LaNiO3 device configuration. The resistance ratio of high resistance state (HRS) to low resistance state (LRS) of the devices was
as high as three orders of magnitude. The dominant conduction mechanisms of LRS and HRS were dominated by ohmic behavior and
trap-controlled space charge limited current, respectively. The resistance switching mechanism of the devices was discussed
using a modified Schottky-like barrier model taking into account the movement of oxygen vacancies. 相似文献
3.
Hongzhi Luo Guodong Liu Fanbin Meng Jianqiang Li Enke Liu Guangheng Wu 《Journal of magnetism and magnetic materials》2012
The electronic structure and magnetic properties of new Fe-based Heusler alloys Fe2TiZ (Z = Ga, Ge, As, In, Sn and Sb) have been studied by first-principles calculations. In these alloys, the 24-electron Fe2TiGe, Fe2TiSn are nonmagnetic semiconductors and other compounds are all ferrimagnetic metals. Fe2TiAs and Fe2TiSb are predicted to be half-metals with 100% spin polarization. The spin polarization ratio in Fe2TiGa and Fe2TiIn is also quite high. The calculated total moment for Fe2TiAs and Fe2TiSb is 1 μB, which is mainly determined by the Fe partial moment. The half-metallicity of Fe2TiSb is stable under lattice distortion. The spin polarization of Fe2TiSb is found to be 100% for the lattice variation in a range of 5.6–6.1 Å, which is attractive in practical applications. 相似文献
4.
Guodong Liu Jinglan Chen Zhuhong Liu Guangheng Wu F.R. de Boer Yangxian Li 《Solid State Communications》2004,130(10):687-690
We report the detailed observation of martensitic variants in NiMnGa single crystals. The variants that are twinned with each other in different ways can be clearly identified in our single crystals by optical observation. We also investigated the preferential orientation of the martensitic variants in NiMnGa single crystals. We observed the motion of the variant boundary in response to application of a magnetic field. This observation can be used to explain phenomenologically the magnetic-field-induced strain. In the single crystal with composition Ni52Mn24Ga24, martensite with seven modulated layers (7M) shows preferentially oriented variants. A completely recoverable two-way shape-memory behavior was also observed by measuring the free sample in three different directions during a complete temperature cycle. It was found that the largest strains in the [001] and [010] directions occur in different temperature ranges. 相似文献
5.
We proved some results on the dispersion of the real quadratic irrational numbers, and use LEO 386/25 to compute some numerical results for discriminant <200 (see the attached Table A).The project was supported by a grant from NNSF of P.R. China. 相似文献
6.
Hongzhi Luo Fanbin MengYanqiang Cai Wangwen HongEnke Liu Guangheng WuXiaoxi Zhu Chengbao Jiang 《Journal of magnetism and magnetic materials》2011,323(17):2323-2327
Quaternary Heusler alloys Fe1.5M0.5CoSi with M=V, Cr, Mn and Fe have been investigated theoretically and experimentally. All of these samples crystallize in the ordered Heusler-type structure. The calculated electronic structure shows a pseudogap around EF in the minority spin states of Fe2CoSi. With the substitution of low-valent atoms for Fe, the majority antibonding peak is shifted to higher energy and a minority gap around the Fermi level is opened. High spin polarization ratio is obtained in Fe1.5M0.5CoSi (M=V, Cr, Mn) alloys. The calculated total spin moments decrease with decreasing number of valence electrons and follow the Slater-Pauling curve, which agree with the experimental results well. The Curie temperature decreases as M atom varies from Fe to V, but is always higher than 650 K, which is suitable for technical applications. 相似文献
7.
8.
Xinman Chen Hong Zhou Guangheng Wu Dinghua Bao 《Applied Physics A: Materials Science & Processing》2011,104(1):477-481
A heterojunction structure of p-NiO/n-Mg0.6Zn0.4O with an aim to tuning or improving the resistive switching properties was fabricated on Pt/TiO2/SiO2/Si substrates by the sol-gel spin-coating technique. The Pt/NiO/Mg0.6Zn0.4O/Pt heterojunction thin-film device shows excellent resistive switching properties, such as a reduced threshold current of
1 μA for device initiation, a small dispersion of reset voltage ranging from 0.54 to 0.62 V, long retention time and a high
resistance ratio of high-resistance state to low-resistance state about six orders of magnitude. These results indicate that
the resistive switching properties can be greatly improved by constructing the p-NiO/n-Mg0.6Zn0.4O heterojunction for nonvolatile memory applications. The physical mechanism responsible for colossal resistive switching
properties of the heterojunction was analyzed based on interfacial defect effect and formation and rapture of conductive filaments. 相似文献
9.
Fe0.95Pd0.05 nanowires were fabricated by the electrodeposition in porous anodic aluminum oxide templates and post-annealed at 300–700 °C. Transmission electron microscopy observations demonstrated the isolated nanowires to have polycrystalline structure. Magnetic measurements, however, showed improvement of both coercivity and squareness with the addition of 5 at% Pd in the Fe nanowires as well as proper annealing temperatures of about 500 °C. 相似文献
10.
Hongzhi Luo Fanbin Meng Heyan Liu Jianqiang Li Enke Liu Guangheng Wu Xiaoxi Zhu Chengbao Jiang 《Journal of magnetism and magnetic materials》2012
The origin of the Slater–Pauling curve Mt=Zt−28 (Here Mt is the total spin moment and Zt is the number of valence electrons) in half-metallic Heusler alloys Mn2CuZ (Z=Ge and Sb) has been studied in detail. In Mn2CuZ the half-metallic gap has a similar origin like half-Heusler alloys. The Cu atom acts as an electron “donator” in Mn2CuZ, which contributes five d-electrons to the minority spin band of Mn2CuZ. So there are 14 valence electrons in the minority band of Mn2CuZ below the Fermi level. This is the origin of the S–P curve Mt=Zt–28. Finally, it is found that, by partial doping of Cu to the vacant site of half-metallic half-Heusler alloys, the magnetic moments of these can be tuned without destroying the half-metallicity. This can be a possible way to design new half-metals. 相似文献